The world's richest individuals are piling into properties in the world's most expensive cities, pushing up prices of luxury homes.

The value of luxury residential property across the world rose by an average of about two per cent last year, based on prices in the 100 locations covered by Knight Frank's Prime International Residential Index (PIRI).

Four of the top 10 spots went to the United States, as New York (18.8 per cent) and Aspen (16 per cent) took first and second place.

And across the US, average luxury property prices rose almost 13 per cent, pushing it way ahead of the competition in Europe, which achieved an average of 2.5 per cent growth.

However, London's prime property market remained stagnant, largely due to recent changes the stamp duty. When the changes were announced, wealthy buyers rushed transactions through in order to avoid the sting.

"Recent hikes in stamp duty ... have curtailed the rate of price growth for properties worth over £2m in London, holding overall prime price growth at 5.1 per cent for the year," the report said.